1. Field of the Invention
The present invention relates to extracorporeal blood treatment devices and more particularly to a blood oxygenator, an inexpensive portion of which can be disposed of and an expensive portion of which can be sterilized and reused.
2. The Prior Art
Cardiopulmonary bypass circuits have historically been used as an integral part of much modern heart surgery. The purpose for the cardiopulmonary bypass circuit is to permit blood to be pumped, oxygenated and defoamed extracorporeally.
Historically, a bubble oxygenator has been used in the circuit to replace temporarily the biological functions of the lungs. It is found, however, that conventional oxygenators when applied to a patient's blood extracorporeally developed a two-fold problem. First, gas trapped within the blood caused foaming which foam must be removed before the blood could be returned to the patient's body. Second, the comparatively long time duration with which the blood is conducted outside of the patient's body required a heat exchanger to maintain essential body temperature in the blood. In the earliest configuration of known devices, the heat exchanger and the oxygenator were two separate devices in the same circuit.
More recently, however, oxygenators have been utilized which combine the heat exchanger and the oxygenator functions in a single device. Either with or without a heat exchanger conventional oxygenators typically have convoluted flow paths attenuated with a plurality of filters, dispersion plates and the like. The conventional oxygenators mentioned tend to trap blood in the circuit in such a manner as to make it impossible to completely clean or remove the blood from the oxygenator and attendant heat exchanger. Accordingly, the entire oxygenator must be disposed of and cannot be safely reused.
Often, one of the more expensive and complicated portions of the extracorporeal blood circuit is the heat exchanger. It has been found on prior art devices that those heat exchangers which are an integral part of the oxygenators are disposable therewith thereby incurring significant unnecessary costs.
It would be desirable, therefore, to provide an improved blood oxygenator with a sterilizable and reusable heat exchange element easily used with and separable from a disposable portion of the oxygenator containing the more complex and nonsterilizable blood circuit.